This invention relates to aircraft emergency evacuation systems employing inflatable escape slides packed in stowage packs and more particularly relates to an apparatus for automatically deploying the stowage pack containing such inflatable escape slide through a doorway.
Emergency evacuation systems that employ inflatable escape slides are installed on virtually all passenger-carrying aircraft to provide rapid evacuation of the passengers and crew during on-ground emergencies, such as those following an emergency landing or a ditching at sea. During normal aircraft operation, the deflated escape slide is generally packed in a compact package or container that is mounted on the interior surface of the aircraft door or on the floor of the aircraft at a position adjacent the door. In most systems, the upper end of the escape slide includes a girt that encompasses a girt bar that is connected to the aircraft floor at a position immediately inside the door. In the event of an emergency, the door is opened and the escape slide is automatically or manually moved through the doorway and inflated so as to form a slide that extends downwardly from the door sill to the surface of the ground or water.
It can be readily recognized and is well known in the art that numerous design and manufacturing constraints apply to emergency evacuation systems of the above-described type. For example, the system should be capable of rapid actuation and deployment to facilitate speedy evacuation of the aircraft. Generally, this requires an automatic deployment sequence that is initiated by simply actuating the aircraft door or by some other simple operation that is easily implemented by a passenger or crewmember. To permit use of the door during nonemergency conditions, an arming and disarming device must be provided that can be activated by a crewmember in response to the given situation.
Various types of doors are employed in modern aircraft and the evacuation system must be either specifically configured for a particular type of door or must be adapted or adaptable thereto. For example, in prior art evacuation systems that operate in conjunction with a plug-type door, of the variety wherein the door is opened by moving it outwardly and then longitudinally in the direction that is generally parallel to the outside of the aircraft, a stowed evacuation system is positioned adjacent the door so as to be available should an emergency condition develop. In another type of escape slide the deflated slide is stowed within the lower portion of the door and is ejected therefrom as the door is moved outwardly during an emergency evacuation procedure. In the more preferred arrangements for use with overhead doors, the evacuation system is oftentimes attached to the interior of the door and moves upwardly with the door when it is opened under normal, nonemergency conditions. With this type of arrangement, the stowed evacuation system remains attached to the aircraft floor by means of a girt bar or other fastening arrangement when such an overhead door is moved upwardly for emergency evacuation. As the door reaches a predetermined height, the stowed evacuation system is either forcibly ejected or falls from the door under the force of gravity and the escape slide is inflated by means of aspirators or turbine-type air pumps. In each of these systems, the girt bar usually must be locked into place in front of the aircraft door to arm the evacuation system and must be disconnected therefrom so that the door can be utilized without deploying the escape slide. Such a system may or may not be usable with or adaptable to various other types of doors, such as the upwardly and outwardly swinging emergency door of the type that is presently used on commercial aircraft such as the Boeing 747.
An escape slide stowage pack for use with an outwardly and upwardly swinging door is described and illustrated in U.S. Pat. No. 4,375,877 issued Mar. 8, 1983 to Thomas H. Shorey and owned by the assignee of the present application. The emergency evacuation system described in the aforementioned patent is configured so that the deflated escape slide and compressed gas cylinders and turbine-type pumps for inflating the escape slide are contained in a stowage pack that is formed by a plurality of hinged together, substantially rectangular links hingedly attached to the packboard that facilitate the system deployment. More specifically, the system packboard is basically a shell-like structure having a bottom panel, two upwardly extending side panels and a back panel that interconnects the two side panels. When the system is assembled for stowage in the aircraft, substantially rectangular, hinged together links extend between the packboard bottom and the back panel to form the top and fourth side surface of the stowage pack with the longitudinal edge of the links being hinged to the upward edge of the packboard back panel. To facilitate stowage of the evacuation system in a position closely adjacent an outwardly and upwardly swinging escape door, the forward edges of the packboard side panels extend upwardly from the packboard bottom panel and are angularly directed toward the packboard back panel. In this arrangement, one of the rectangular links forms the top surface of the stowage package and the two remaining rectangular links extend along the two angularly projecting regions of the packboard side panels to form the forward face of the slide stowage pack. The longitudinal edge at the lowermost link is hinged to one edge of a baseplate that can be securely interconnected with the aircraft floor at a position adjacent the associated escape door. In particular, the baseplate, links, and packboard are interconnected so that the links permit the packboard to swing arcuately downward and against the outer surface of the aircraft fuselage. In addition, the system baseplate is preferably configured and arranged to permit the evacuation system stowage pack to be moved away from the door with relative ease so that the door can be utilized for aircraft servicing and other nonemergency uses.
In operation, the emergency evacuation system is stowed in the above-described shell and is secured to the aircraft floor adjacent the interior of the associated emergency door. It is necessary to provide a deployment system for moving the packboard out through the door when it is opened under emergency conditions. Typically, the deployment device need only pull the assembled stowage pack far enough outside the door so that the force of gravity will carry the pack out through the door deploying the slide.
It is therefore an object of the present invention to provide a deployment system for an escape slide pack for use with an outwardly and upwardly swinging door that can be positively latched to the door to reliably deploy the slide in every instance due to the critical nature of the proper functioning of the escape slide assembly.
It is further an object of the invention to provide such a deployment system that is easily armed and disarmed so that the door can be opened without deploying the emergency escape slide pack in nonemergency situations.
It is further an object of the invention to provide a deployment system for the escape slide pack that will operate to move the pack sufficiently through the door to allow deployment of the pack by the force of gravity even in conditions in which the aircraft is not in a level position with respect to the ground, but is tilted to some degree.